In order to test thoroughly a wound component such as a transformer, it is necessary to measure a variety of parameters such as: the winding resistance (of both the primary and secondary windings), the turns ratios, the winding inductance or magnetising current and the interwinding capacitance. It is also usual to test the insulation at both high and low voltage levels, These parameters are conventionally measured by sequentially connecting the transformer to a series of separate pieces of test equipment each of which is dedicated to testing one particular parameter. Such testing thus requires several, usually expensive and relatively large pieces of equipment, to test fully the transformer. At each stage, the transformer has to be electrically connected to the relevant test equipment, the test carried out, then electrically disconnected and moved on to the next piece of test equipment and the operation repeated for each test to be carried out. This procedure is time consuming and error prone as wires may be wrongly connected, measuring equipment mis-read, results incorrectly recorded etc.
Apparatus has also been provided for automatically and sequentially connecting a transformer to a plurality of separate pieces of test equipment using a matrix of relays under the control of a computer. This automates the connecting and disconnecting of the various pieces of test equipment but a separate piece of equipment is still required to carry out each test. This means that a benchful of equipment is still required to test a component which itself may be relatively small, e.g. with maximum dimensions in the order of 10-20 cms. The lengthy leads required to connect the different pieces of equipment also makes some measurements difficult, e.g. high frequency tests with leads over 2 m in length. This form of test apparatus is also still relatively slow, e.g. taking 30 seconds or more to test a transformer fully, and is of necessity relatively expensive.
This invention aims to provide test apparatus which is much more compact than such known arrangements yet is able to carry out all the tests required quickly and accurately.